Step 1: Problem Definition:
Given a dataset with a mean of 21 and a median of 23, determine the mode.
Step 2: Empirical Relationship:
For moderately skewed distributions, the relationship between mean, median, and mode is empirically defined as:
\[
\text{Mode} = 3 \times \text{Median} - 2 \times \text{Mean}
\]
This formula is applicable to approximately symmetrical or normally distributed data.
Step 3: Calculation:
Substitute the given values into the formula:
\[
\text{Mode} = 3 \times 23 - 2 \times 21
\]
Calculate the result:
\[
\text{Mode} = 69 - 42 = 27
\]
Step 4: Result:
The mode of the dataset is \( 27 \).